3-Hydroxyalkyl phosphine oxide flame retardant compositions

Abstract

Thermoplastic polyphenylene oxide compositions such as polyphenylene oxide that has been modified with high impact polystyrene are rendered fire retardant by the addition of an effective amount of a 3-hydroxyalkyl phosphine oxide such as n-butyl bis(3-hydroxypropyl) phosphine oxide.

We claim: 
     
       1. A polyphenylene oxide composition rendered flame retardant by having combined therewith an effective amount of 3-hydroxyalkyl phosphine oxide having the formula: ##STR3## wherein R 1  may be the same or a different radical selected from the group consisting of hydrogen, and the methyl radical, R 2  is an alkyl radical of 4 to 8 carbon atoms and n is either zero or one. 
     
     
       2. The flame retardant composition of claim 1 wherein the phosphine oxide is tris(2-methyl-3-hydroxypropyl) phosphine oxide. 
     
     
       3. The flame retardant composition of claim 1 wherein the phosphine oxide is tris(3-hydroxypropyl) phosphine oxide. 
     
     
       4. The flame retardant composition of claim 1 wherein the phosphine oxide is n-butyl bis(3-hydroxypropyl) phosphine oxide. 
     
     
       5. The flame retardant composition of claim 1 wherein the phosphine oxide is s-butyl bis(3-hydroxypropyl) phosphine oxide. 
     
     
       6. The flame retardant composition of claim 1 wherein the phosphine oxide is 2-methyl-3-hydroxypropyl bis(3-hydroxypropyl) phosphine oxide. 
     
     
       7. The flame retardant composition of claim 1 wherein said polyphenylene oxide composition contains about 35 parts by weight polyphenylene oxide and about 65 parts by weight of a polystyrene resin. 
     
     
       8. The flame retardant composition of claim 1 wherein said polyphenylene oxide composition contains about 40 parts by weight polyphenylene oxide and about 60 parts by weight of a polystyrene resin. 
     
     
       9. The flame retardant composition of claim 7 wherein the polystyrene present in said composition is a high impact polystyrene. 
     
     
       10. The flame retardant composition of claim 1 to which has been added about 5 parts per hundred of tris(2-methyl-3-hydroxypropyl) phosphine oxide. 
     
     
       11. The flame retardant composition of claim 1 to which has been added about 5 to about 6 parts per hundred of tris(3-hydroxypropyl) phosphine oxide. 
     
     
       12. The flame retardant composition of claim 1 to which has been added about 4.25 to about 6.5 parts per hundred of s-butyl bis(3-hydroxypropyl) phosphine oxide. 
     
     
       13. The flame retardant composition of claim 1 to which has been added about 5 parts per hundred of 2-methyl-3-hydroxypropyl bis(3-hydroxypropyl) phosphine oxide. 
     
     
       14. A method of manufacturing a flame retardant polyphenylene oxide composition which comprises adding thereto an effective amount of a 3-hydroxyalkyl phosphine oxide having the formula: ##STR4## wherein R 1  may be the same or a different radical selected from the group consisting of hydrogen and the methyl radical, R 2  is an alkyl radical of 4 to 8 carbon atoms and n is either zero or one. 
     
     
       15. The method of claim 14 wherein the phosphine oxide is tris(3-hydroxypropyl) phosphine oxide. 
     
     
       16. The method of claim 14 wherein the phosphine oxide is tris(2-methyl-3-hydroxypropyl) phosphine oxide. 
     
     
       17. The method of claim 14 wherein the phosphine oxide is 2-methyl-3-hydroxypropyl bis(3-hydroxypropyl) phosphine oxide. 
     
     
       18. The method of claim 14 wherein the phosphine oxide is s-butyl bis(3-hydroxypropyl) phosphine oxide. 
     
     
       19. The method of claim 14 wherein said polyphenylene oxide composition contains about 35 parts by weight polyphenylene oxide and about 65 parts by weight of a polystyrene resin. 
     
     
       20. The method of claim 14 wherein said polyphenylene oxide composition contains about 40 parts by weight polyphenylene oxide and about 60 parts by weight of a polystyrene resin. 
     
     
       21. The method of claim 14 wherein the polyphenylene oxide composition contains a high impact polystyrene resin. 
     
     
       22. The method of claim 14 wherein about 5 parts per hundred of tris(2-methyl-3-hydroxypropyl) phosphine oxide is added to said polyphenylene oxide composition. 
     
     
       23. The method of claim 14 wherein about 5 to about 6 parts per hundred of tris(3-hydroxypropyl) phosphine oxide are added to said polyphenylene oxide composition. 
     
     
       24. The method of claim 14 wherein about 4.5 to about 6.5 parts per hundred of s-butyl bis(3-hydroxypropyl) phosphine oxide are added to said polyphenylene oxide composition.